4.5L Duramax Diesel

Duramax LB7 Specs

Duramax LBZ Specs

Duramax LLY Specs

Duramax LMM Specs

Duramax LML Specs







Return to Duramax Diesel Specs.


4.5L Duramax

Duramax LMK Specs






General Motors, without the help of joint venture partner Isuzu, designed the 4.5L Duramax as an alternative to V-8 gasoline engines in their line of 1/2 ton trucks (Chevrolet Silverado and GMC Sierra 1500). Production was initially projected for the 2010 model year, but finiancial woes forced GM to scrap the project. At this time it is unknown if and when the 4.5L Duramax, or Duramax 4500, will go into production. The engine described on this page was GM's initial prototype.



4.5L Duramax Specs


4.5L Duramax LMK, 72 degree V-8.


275 cubic inches, 4.5 liters.

Compression Ratio:

16.0 : 1


Single variable geometry turbocharger, air-to-air intercooler.


29,000 psi high pressure common rail with piezo injectors.


Dual overhead camshaft, 32 valve, 4 valves per cylinder.

Emissions Equipment:

Proposed EGR, DOC, SCR, and DPF systems.

Peak Horsepower:

Est. 310 horsepower.

Peak Torque:

Est. 520 lb-ft.


4.5L Duramax Info

• Designed specifically for use in the GMC Sierra 1500 and Chevrolet Silverado 1500 pickups.
• Compacted graphite iron engine block (CGI) and aluminum cylinder heads.
• Estimated 25 percent increase in fuel economy over similar gasoline powered truck under light load conditions.
• Estimated 40 - 70 percent increase in fuel economy over similar gasoline powered truck under higher load conditions (towing/hauling).
• General Motors financial crisis put a hault on the 4.5L Duramax, which was projected to be available for the 2010 model year. Whether or not the engine will see production is a mystery, but highly unlikely.
• The only Duramax designed without the help of diesel partner Isuzu.
• The 4.5L Duramax features a unique head design in which the exhaust manifolds exit into the engine valley while the intake portion of the head is located on the top of the cylinder head. Doing so increases the thermal efficiency of the turbocharger, which has been placed in the engine valley.
• The Duramax 4500 does not have intake manifolds.
• GM utilized a 72 degree V configuration in order to make the engine narrower. Doing so allows the engine to fit virtually anywhere a small block Chevrolet gasoline engine will.
• The proposed 4.5L would meet tier 2 Bin 5 emissions requirements, making it 50-state legal.